Biocomposite material

Abstract

The present invention relates generally to biocomposite materials made of cellulose and wheat bran and/or oat husk, prepared by methods comprising mixing the husk or bran with an aqueous alkaline solution, stirring and/or homogenizing the mixture, admixing with cellulose pulp and thermoforming the material under conditions admitting curing, thereby obtaining improvements in strength measured as at least one of strain at peak (%), stress at peak (%) and Young's modulus (MPa).

The invention claimed is: 
     
       1. A process for preparing a biocomposite material comprising a bioadditive from cereal husks and/or brans, said process comprising the steps:
 (a) mixing the cereal husk and/or bran with an aqueous alkaline solution with a pH of at least 7, in order to provide a bioadditive, 
 (b) admixing the bioadditive with a dispersion of cellulose pulp to provide a biocomposite material; 
 (c) diluting the mixture of bioadditive and cellulose pulp to a level of 0.25 to 2% dry fiber; 
 (d) collecting the diluted mixture in a sieve or on a filter; and 
 (e) thermoforming the collected mixture to form the biocomposite material, thereby curing said biocomposite material. 
 
     
     
       2. A process for preparing a biocomposite material comprising a bioadditive from cereal husks and/or brans, said process comprising the steps:
 (a) mixing the cereal husk and/or bran with an aqueous alkaline solution with a pH of at least 7, in order to provide a bioadditive, 
 (b) collecting a water soluble fraction of the bioadditive from step (a) and admixing the water soluble fraction of the bioadditive with a dispersion of cellulose pulp to provide a biocomposite material; and 
 (c) thermoforming the biocomposite material, thereby curing said biocomposite material. 
 
     
     
       3. The process according to  claim 1 , wherein the ratio of cereal husk or bran to aqueous solution in the mixing step (a) is from at least 1:1 to 1:100. 
     
     
       4. The process according to  claim 1 , wherein the biocomposite material comprises 75% (wt) or less of the bioadditive. 
     
     
       5. The process according to  claim 1 , wherein the mixing step comprises stirring and/or homogenization wherein the rpm is 30,000 rpm or less. 
     
     
       6. The process according to  claim 1 , wherein the cereal husk or bran is selected from at least one of wheat brans and oat husks. 
     
     
       7. The process according to  claim 1 , wherein the alkaline solution of step (a) comprises at least 0.5% (wt) NaOH. 
     
     
       8. The process according to  claim 1 , comprising adding an additive in at least one of step (a) and step (b), said additive being selected from at least one of cationic starch; AKD (alkylketene dimer); ASA (alkenylsuccinic anhydride); PLA (poly lactic acid); dyes; fillers; pigments; wet strength increasing agents; defoamers; preservatives; and biocides. 
     
     
       9. The process according to  claim 1 , wherein the biocomposite material comprises 5 to 50% (wt) or less of the bioadditive. 
     
     
       10. The process according to  claim 1 , wherein the biocomposite material is prepared without the addition of a binder. 
     
     
       11. The process according to  claim 1 , wherein in step (a), the husk or bran has not been subjected to an acid treatment prior to mixing with the aqueous alkaline solution. 
     
     
       12. The process according to  claim 1 , wherein in step (a), the husk or bran has not been chemically treated prior to mixing with the aqueous alkaline solution.